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New constraints on the evolution of 87Sr/86Sr of seawater during the Upper Triassic

Kovács, Zsófia LU ; Demangel, Isaline LU orcid ; Richoz, Sylvain LU ; Hippler, Dorothee ; Baldermann, Andre and Krystyn, Leopold (2020) In Global and Planetary Change 192.
Abstract

The Late Triassic time interval witnessed several important biological turnovers, extinctions and onset of new life forms. Therefore, it is crucial to better constrain the tectonic, climatic and oceanographic framework at this time. The radiogenic strontium isotopic composition (87Sr/86Sr) of seawater, recorded in marine carbonates is sensitive to variations in continental weathering and oceanic spreading rates. This makes it a powerful proxy for palaeo-environmental reconstructions and an excellent global stratigraphic correlation tool of marine sediment records. In this study, we present a new and extended 87Sr/86Sr dataset across the late Norian - Hettangian interval, established from... (More)

The Late Triassic time interval witnessed several important biological turnovers, extinctions and onset of new life forms. Therefore, it is crucial to better constrain the tectonic, climatic and oceanographic framework at this time. The radiogenic strontium isotopic composition (87Sr/86Sr) of seawater, recorded in marine carbonates is sensitive to variations in continental weathering and oceanic spreading rates. This makes it a powerful proxy for palaeo-environmental reconstructions and an excellent global stratigraphic correlation tool of marine sediment records. In this study, we present a new and extended 87Sr/86Sr dataset across the late Norian - Hettangian interval, established from carbonate successions in Austria and Turkey. The well-established biostratigraphy and high sampling resolution allow evaluating changes in the 87Sr/86Sr record with a better time constraint than in previous studies. An exceptionally sharp trend towards unradiogenic values has been observed in the latest Norian and in the early Rhaetian from 0.70800 to 0.70779. Considering Late Triassic climate change, updated tectonic models and actual dating of magmatic events, possible explanations for the observed trend in the 87Sr/86Sr record are: (i) enhanced dissolution of pre-Norian carbonates, (ii) dissolution of widespread Late Triassic evaporites and (iii) tectonic reorganization of sedimentary basins due to the break-up of the supercontinent Pangea. At the very end of the Choristoceras marshi Zone, in the late Rhaetian, the unradiogenic 87Sr/86Sr trend is reversed. This is likely related to environmental changes due to the continental emplacement of the Central Atlantic Magmatic Province.

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author
; ; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Hettangian, Norian, Palaeo-environment, Radiogenic strontium, Rhaetian, Seawater evolution, Triassic/Jurassic boundary
in
Global and Planetary Change
volume
192
article number
103255
publisher
Elsevier
external identifiers
  • scopus:85086461587
ISSN
0921-8181
DOI
10.1016/j.gloplacha.2020.103255
language
English
LU publication?
yes
id
4fbf43ef-6790-42f1-8eac-9a9e9c00b06a
date added to LUP
2020-06-30 10:00:23
date last changed
2024-03-20 11:45:47
@article{4fbf43ef-6790-42f1-8eac-9a9e9c00b06a,
  abstract     = {{<p>The Late Triassic time interval witnessed several important biological turnovers, extinctions and onset of new life forms. Therefore, it is crucial to better constrain the tectonic, climatic and oceanographic framework at this time. The radiogenic strontium isotopic composition (<sup>87</sup>Sr/<sup>86</sup>Sr) of seawater, recorded in marine carbonates is sensitive to variations in continental weathering and oceanic spreading rates. This makes it a powerful proxy for palaeo-environmental reconstructions and an excellent global stratigraphic correlation tool of marine sediment records. In this study, we present a new and extended <sup>87</sup>Sr/<sup>86</sup>Sr dataset across the late Norian - Hettangian interval, established from carbonate successions in Austria and Turkey. The well-established biostratigraphy and high sampling resolution allow evaluating changes in the <sup>87</sup>Sr/<sup>86</sup>Sr record with a better time constraint than in previous studies. An exceptionally sharp trend towards unradiogenic values has been observed in the latest Norian and in the early Rhaetian from 0.70800 to 0.70779. Considering Late Triassic climate change, updated tectonic models and actual dating of magmatic events, possible explanations for the observed trend in the <sup>87</sup>Sr/<sup>86</sup>Sr record are: (i) enhanced dissolution of pre-Norian carbonates, (ii) dissolution of widespread Late Triassic evaporites and (iii) tectonic reorganization of sedimentary basins due to the break-up of the supercontinent Pangea. At the very end of the Choristoceras marshi Zone, in the late Rhaetian, the unradiogenic <sup>87</sup>Sr/<sup>86</sup>Sr trend is reversed. This is likely related to environmental changes due to the continental emplacement of the Central Atlantic Magmatic Province.</p>}},
  author       = {{Kovács, Zsófia and Demangel, Isaline and Richoz, Sylvain and Hippler, Dorothee and Baldermann, Andre and Krystyn, Leopold}},
  issn         = {{0921-8181}},
  keywords     = {{Hettangian; Norian; Palaeo-environment; Radiogenic strontium; Rhaetian; Seawater evolution; Triassic/Jurassic boundary}},
  language     = {{eng}},
  publisher    = {{Elsevier}},
  series       = {{Global and Planetary Change}},
  title        = {{New constraints on the evolution of <sup>87</sup>Sr/<sup>86</sup>Sr of seawater during the Upper Triassic}},
  url          = {{http://dx.doi.org/10.1016/j.gloplacha.2020.103255}},
  doi          = {{10.1016/j.gloplacha.2020.103255}},
  volume       = {{192}},
  year         = {{2020}},
}